Conventionally, a leadframe is manufactured in such way that a pattern of the leadframe is formed from a metal plate by etching or press processing, then, after palladium plating is carried out to the whole surface of it, semiconductor elements are mounted on the predetermined position, and then, after sealing with resin, cutting is carried out by using a die etc. Finally, separate chips are produced. Such products are in practical use as electronic parts as IC chips.
In recent years, in a specification of the leadframe, the use of coating by solder plating containing lead has ceased in consideration of the influence on environment, and palladium plating to the whole surface of the leadframe has been used. However, since palladium is an expensive metal material, there is a problem of raising the product cost by using palladium plating to the whole surface.
Accordingly, the main object of the present invention is to provide a cheaper leadframe by minimizing the amount of palladium used.
Other object of the present invention is to provide a manufacturing method of leadframe by which the fault of the leadframe is eliminated.